Predetermined torque release wrench



Dec. 12, 1961 c. DRACKA 3,012,456

PREDETERMINED TORQUE RELEASE WRENCH Filed Oct. 22, 1959 2 Sheets-Sheet 1 lNVENTOR I ELAREN/JB L. .UIZAEKA ATTORNEY Dec. 12, 1961 c. DRACKA PREDETERMINED TORQUE RELEASE WRENCH 2 Sheets-Sheet 2 Filed Oct. 22. 1959 lNVENTOR fimzzwzl. 171245251.

United States Patent fl-ice 3,612,455 Patented Dec. 12, 1961 3,012,456 PREDETTJRMINED TORQUE RELEASE WRENCH Clarence L. Dracka, Port Ciinton, Ohio, assignor to Port iinton Manufacturing Company, Port Clinton, Ohio, a corporation of Ohio Filed st. 22, 1959, Ser. N 848,127 Ciaims. (Q1. S152.4)

This invention relates to wrenches and more particularly to a wrench of the predetermined torque type embodying means for predetermining the amount of force or torque applied in drawing up or tightening threaded members such as securing bolts, nuts, screws and other rotatable mechanical means.

The invention embraces the provision of a predetermined torque wrench of a character embodying a drive or torque transmitting connection between engaging components of the wrench construction which is automatically released when a predetermined limit of applied force is attained during operation of the wrench.

The invention has for an object the provision of a pre determined torque wrench embodying a resiliently biased torque transmitting connection of an adjustable charac ter wherein the drive connection is automatically released upon the application of a predetermined force, the wrench construction embodying a calibrated adjustable means for establishing a maximum amount or release limit of force transmitted through the wrench to the work.

Another object of the invention is the provision of an adjustable predetermined torque wrench wherein the components of the wrench construction are enclosed within a housing protecting the components from moisture and the ingress of foreign matter.

Another object of the invention i the provision of a predetermined torque wrench construction which is reliable in its operation and which may be made in various sizes for use with various types and sizes of mechanical securing devices or rotatable devices where it is desirable to limit the transmitted torque.

Further objects and advantages are within the scope of this invention such as relate to the arrangement, operation and function of the related elements of the structure, to various details of construction and to combinations of parts, elements per se, and to economics of manufacture and numerous other features as will be apparent from a consideration of the specification and drawing of a form of the invention, which may be preferred, in which:

FIGURE 1 is a side elevational view of a form of wrench construction of the invention;

FIGURE 2 is a longitudinal vertical sectional view through the wrench construction shown in FIGURE 1;

FIGURE 3 is a top plan view of the construction shown in FIGURE 2;

FIGURE 4 is an isometric view of one of the components of the releasable torque transmitting means of the wrench construction;

FIGURE 5 is a detail sectional view taken substantially on the line 55 of FIGURE 2;

FZGURE 6 is a transverse sectional view taken subsentially on the line 66 of FIGURE 5;

FIGURE 7 is an elevational view of a drive shaft forming a component of the wrench construction;

FIGURE 8 is an elevational view, partly in section illustrating the components of the torque transmission connection in release position;

FIGURE 9 is a sectional View illustrating a modified form of the wrench construction of the invention;

FIGURE 10 is a sectional view illustrating another form of the wrench construction;

FIGURE 11 is an isometric view of a form of socket tool usable with the wrench construction of the invention;

FIGURE 12 is a fragmentary detail sectional view illustrating a modified form of means for preventing relative rotation of one of the torque transmitting components of the wrench, and

FIGURE -13 is a detail sectional view illustrating another form of means for preventing relative rotation of one of the components of the torque transmitting connection.

While the forms of the invention illustrated are particularly adapted for accommodating socket means or tools for drawing up or tightening bolts, nuts or various threaded securing devices, it is to be understood that the apparatus of the invention may be employed wherever it is desirable to apply a predetermined maximum rotative force or torque in a work performing operation.

Referring to the drawings in detail, one form of the invention is illustrated in FIGURES 1 through 8. The arrangement shown therein is inclusive of a hollow cylindrical or tubular casing or housing 18 formed of metal, one end of which is closed by a bottom or wall 12 which is integrally formed with a projecting portion or tenon 14 of polygonal shape, which in the embodiment illustrated is of square cross-section. The projection 14 is adapted to be received in a reciprocally shaped opening 16 in a socket member or tool 18, the socket member being formed with a polygonally shaped opening 20 of a dimension to slidably fit over a nut 22, bolt head, or other securing device to be drawn tight through the utilization of the wrench construction of the invention.

The tenon or projection 14 is formed with a transverse bore accommodating an expansive coil spring 24 engaging a ball or detent member 26, the ball being maintained within the entrance of the bore by staking or swaging indicated at 28. The spring-biased ball 26 engages an inner surface of a socket or tool received on the projection 14 to frictionally retain the socket on the tenon but permitting ready removal of the socket when desired. A circumferential region or area 30 of the exterior surface of the cylinder 10 may be knurled to facilitate manual handling of the housing 10 during operation of the wrench construction.

The interior of the housing 10 is formed with a circular cylindrical wall in which is slidably fitted a metal sleeve 32 forming a component of the torque transmitting or drive connection of the Wrench construction.

The exterior surface of the region at the open end of the housing 10 is threaded as at 34 to accommodate a threaded closure, cap or member 36. The cap or closure 36 is provided with a boss portion 38 which is bored to accommodate a torque transmitting member or drive shaft 40 which also extends through the hollow interior of the sleeve 32 as shown in FIGURE 2.

The shaft 40 extends through the boss 38 and is integrally formed with a polygonally shaped projection or tenon 42 adapted to receive a manipulating arm or handle 44 which is employed for manually applying force or rotative torque to the shaft 40. The projection 42 is provided with a ball detent 44' which is spring biased in a direction to frictionally engage a wall of a polygonally shaped opening in the handle member 44 to frictionally secure the handle to the shaft 40.

The sleeve 32 and the shaft 40 are formed or provided with interengaging means for transmitting torque from the shaft 4% to the housing It? and through the housing to the socket 18 or other tool provided upon the tenon 14. The end of the shaft contained within the housing 19 is formed with a head portion 4 5 having flat or planar opposed surfaces or faces 48, the head being provided with a bore 56, the aris of which is normal to the planes of the surfaces 4-8. The bore in the head 46 accommodates a pin or shaft 52 which forms journal bearings for rollers or rotatable members 54 as shown in FIGURES Sand 8.

As particularly shown in FIGURES 2, 4 and 8 the lower end region of the sleeve 32, is formed with curved recesses 56, the curvature of which is substantially equal to the radii of the maximum periphery of the rollers 54.

As shown in FIGURE 2 the peripheries of the rollers 54 engage in the recesses 56 to establish a torque'transmi-ttin-g or drive connection between the shaft 49 and the sleeve 32. The peripheral regions of the rollers 54 are curved in transverse directions providing substantially line contacts with the curved surfaces defining the recesses.

The bottom wall 12 of the housing i is intericrly bored to accommodate a hardened thrust member or metal ball fi'which is maintained in the bore by swaging or staking indicated at 6-2. The end of the head 46 on the shaft 40 is formed with a conically shaped recess 64, the walls of which engage the ball 6% in the manner shown in FI URES 2 and 5, the ball serving as a thrust means to resist the end thrust of the shaft as. Through the use of a ball member 69 the friction set up by the and thrust on the shaft 49 is reduced to a minimum.

As the sleeve 32 functions to transmit rotation or torque from the shaft 4%; to the housing 19, means is provided for accommodating lengthwise slidable movement of the sleeve but preventing relative rotation of the sleeve with respect to the housing 3.9. As shown in FIGURES 1 and 2, a generally rectangularly shaped block or member 66 is secured to the housing it by means of screws 68 and is fashioned with a projection or key '70 which extends into a slot or keyway '72 formed in the wall of sleeve 32 to provide for rotation of the housing it} with the sleeve.

Resilient means is provided for biasing the sleeve 32 into engagement with the rollers 54 carried by the shaft 40. As particularly shown in FIGURE 2 the resilient means comprises a series of pairs of dished or concave shaped disks or members 74.

The disks are arranged or disposed in the manner illustrated in FIGURE 2 with the concave configurations of the disks of each pair facing each other, the disks being provided with central openings to accommodate the shaft 40 and thus maintain the disks in alignment. The disks are of spring steel and are hardened to provide resiliency for establishing downward thrust upon the sleeve 32.

Disposed between the interior surface 37 of the cap or closure 36 and the uppermost of the disks 74 is a plurality of flat or planar disks or washers 79 which form a spacing means between the cap 36 and the uppermost of the spring washers or disks 74. The purpose of the spacer disks or washers 7? is to provide for longitudinal adjustment of the cap 36 with respect to the housing, the adjustment being obtained by rotating the cap 36 with respect to the housing 10.

It will be apparent that by rotating the cap or closure 36 with respect to the housing through the threaded interconnection, the compressive pressure upon the disks may be varied or adjusted to thereby regulate or adjust the amount of thrust or pressure upon the sleeve 32 tending to resist disengagement of the rollers 54 from the recesses 56 until the nut 22 or other securing means is drawn up and the force applied to the handle 44 in drawing up the nut exceeds the downward or biasing pressure of the spring disks 74.

When this occurs, the spring disks 74 are further compressed by the increased force in drawing up the nut 22 and the rollers 54 move or ride out of the recesses 56 thus disengaging or breaking the torque transmitting or drive connection so that further application of force on the handle 44 is not transmitted to the nut 22 being drawn up.

Further rotation of the wrench handle or arm 44 merely into and out of the recesses 56 effecting successive slidable movements of the sleeve 32 lengthwise oi the housing 10 but without transmission of additional torque to the housing and the tool or socket 18.

By adjusting the relative position of the cap or closure 3d with respect to the housing 19 through the threaded interconnection the initial compressive pressure on the spring disks 74 may be varied or regulated and hence the amount of torque transmitted to the tool 18 may be regulated and controlled. The exterior peripheral surface of the cap 36 is preferably knurled to facilitate manual gripping and adjustment by the user.

Suitable calibrations or graduations are provided in order to adjust the closure or cap 35 to a position predetermining the torque force at which the drive or torque transmitting connection is to be released in order to control the amount of force to be transmitted to the socket or tool 18. As shown in FIGURE 1, a series of-gra-duations or calibrations 73 are inscribed upon a circumferential area or band 8%"! of the housing 1%) immediately beneath the threaded portion 34 of the housing.

The exterior surface of the cap or closure 36 is provided with an index mark 82 which is adapted for selected registration with the graduations '7 8. The graduations 78 may be spaced to indicate foot pounds of torque at which the torque transmitting connection is released. Thus by rotating the closure as, the index mark 82 is brought into registration with a graduation indicating the desired maximum of torque or force to be applied in drawing up a nut, bolt or other element. 7

it will be apparent from FIGURE 1 that if it is desired to increase the amount or maximum of force to be transmitted in drawing up the nut 22, the cap or closure 36 is rotated in a clockwise direction as viewed in FIGURE 1, which rotation initially further compresses or places the spring disks 74 under additional compression so that a greater force is transmitted before the torque transmitting connection provided by the rollers 54 and the recesses 56 in the sleeve 32 is released.

Rotation or adjustment of the closure 36 in a counterclockwise direction releases the initial compressive pressure on the spring disks 74, thus reducing the maximum amount of torque transmitted to the socket 18. The rollers 54 are preferably of hardened metal to minimize wear of the rollers.

FIGURE 9 illustrates a modificatiorrof the invention wherein the and thrust provided by the spring disks on the driving shaft is transmitted through the rollers to a hardened disk 86 disposed in the housing. As shown in FIGURE 9, the bottom portion 12a of the housing 10:: is provided with a hardened flat metal washer or disk 86 which is directly engaged by the rollers 54a journaled on the pin 52a carried by the torque transmitting shaft 40a. The rollers 54a directly contact the end surfaces of the longitudinally slidable sleeve 32a and cooperate with the recesses 56:: provided at the end of the sleeve to establish a releasable torque transmitting connection,

In this form of the invention a pilot tenou or guide projection 83 may be provided integral with the shaft 40a and projecting downwardly into a bushing nested in a suitable bore in the bottom portion 124: of the housing 10a. The pilot tenon 88, being rotatable in the bushing 90, provides for proper centering at all times of the axis of the shaft 40a and prevents lateral contact of the ends of the pin 52a with the interior wall of thehousin'g 10a.

The hardened metal disk 86 is provided with a central opening to accommodate the tenon 88. It will be apparent that the small area of contact of the rollers with the disk or plate 86 reduces the friction of the operation of the components. The other components of the construction not illustrated in FIGURE 9 are of the same character asthe components shown in the form of the invention illustrated in FIGURES 1 through 8.

FIGURE 10 illustrates another form of the invention. In this form the bottom portion 12b of the housing 10b supports a ball bearing assembly 90 consisting of a lower plate or disk 92 which directly engages the interior surface of the bottom portion 1217, an upper disk or plate 94 which is in direct contact with a lower surface 96 formed on a head portion 98 on the lower end of the drive shaft 40b, and a series of bearing balls between the plates which are spaced by a ball cage 100.

Rollers 54b are journaled upon a pin 52b carried by the head portion 98 and are adapted for cooperation with a recessed sleeve 32b. The thrust on the shaft 4011, set up by the spring pressure acting downwardly upon the sleeve 32b, is resisted by the ball bearing assembly 90 so as to minimize friction.

The head portion 98 of the shaft 4% may be provided with a tenon or guide pilot 104 which extends into a bushing 106 contained in a suitable bore in the bottom portion 12b of the housing.

In order to prevent relative rotation between the sleeve 32b and the housing b, a portion of the housing wall illustrated at 108 may be struck inwardly from the metal of the housing wall providing a key or projection extending into a longitudinal slot or keyway 110 formed in the sleeve 32b. In this arrangement, the slot or keyway 110 extends full length of the sleeve in order to facilitate assembly of the sleeve in the housing. The operation of the arrangement shown in FIGURE 10 is substantially the same as in the constructions heretofore described.

FIGURE, 11 illustrates a form of socket or tool member 112 which is usable with the predetermined torque wrench construction and is provided with a polygonally shaped opening 114 adapted to fit over the tenon or projection formed on the end of the housing of the wrench construction. The socket member 112 is provided with a projecting portion 116 having a planar edge 118 and forms a screwdriver configuration for use in drawing up screws or bolts with slotted heads. It is to be understood that other forms of socket or tool members may be provided which are interchangeable and applicable to the tenon on the housing of the wrench.

FIGURE 12 illustrates another form of means for preventing relative rotation between the wrench housing and the slidable torque transmitting sleeve.

In this form, the wall of the housing 10c is bored and threaded to accommodate the threaded portion 120 of a member 122, the member being provided with a projection or key 124 adapted to extend into a longitudinal slot 126 formed in a sleeve 32c. The head portion of the member 122 may be formed with a polygonally shaped recess 128 to receive a polygonally shaped tool for applying or removing the member 122 in the threaded bore in the housing 10c. The arrangement shown in FIGURE 12 may be used with any of the forms of wrench construction disclosed herein.

Another form of means for preventing relative rotation of the sleeve in the housing is illustrated in FIG- URE 13. In this form the wrench housing 10a is provided with a tapered thread 130 to receive the tapered thread of a member 132 which is provided with a projection or key portion 134 for cooperation in a slot 136 formed in a sleeve 32d. It has been found that a tapered thread having an included angle of about 10 is satisfactory to anchor the member 132 in the housing wall. The means shown in FIGURE 13 may be embodied in any of the forms of the wrench construction.

It is apparent that, within the scope of the invention, modifications and different arrangements may be made other than as herein disclosed, and the present disclosure is illustrative merely, the invention comprehending all reasonable variations thereof.

I claim:

1. A predetermined torque release wrench of the character disclosed, in combination, a tubular housing having a tenon portion adapted to accommodate a work engaging means, a sleeve arranged for slidable movement in said housing and rotational movement with the housing. a shaft in said housing having a portion exteriorly of the housing adapted to receive a manipulating handle, a pin extending transversely through the shaft and having its end portions projecting from the shaft, a rotatable roller journaled on each projecting portion of the pin, said sleeve being formed with recesses arranged to be engaged by said rotatable rollers, a closure member con nected with said housing, spring means disposed between said closure member and said sleeve biasing the sleeve into engagement with the rotatable rollers, said closure member being adjustable relative to said housing for varying the biasing pressure of said spring means to thereby predetermine the force required to effect disengagement of the rotatable rollers with the recesses in the sleeve.

2. A predetermined torque release wrench of the character disclosed, in combination, a tubular housing having a closed end and an open end, means formed on the closed end adapted to accommodate a work engaging tool, a sleeve in the housing having an end formed with recesses, a cover for the open end of the housing having threaded connection with the housing, a shaft in said housing extending through the sleeve and having a portion extending exteriorly of the cover and adapted to accommodate a handle, a transversely extending pin carried by the shaft, a pair of rollers journaled on the pin and engagable in the recesses of the sleeve for establishing a torque transmitting connection between the shaft and sleeve, a plurality of spring disks surrounding the shaft for biasing the sleeve into engagement with the rollers, spacer means disposed between the uppermost of the spring disks and the cover whereby rotation of said cover relative to the housing varies the biasing force of said spring disks, and means establishing a connection between said housing and sleeve whereby rotation of said sleeve effects rotation of the housing.

3. A predetermined torque release wrench of the character disclosed, in combination, a tubular housing having a closed end and an open end, means formed on the closed end adapted to accommodate a work engaging tool, a cover for the open end of the housing, said cover having threaded engagement with the housing for adjustment relative to the housing, a sleeve in the housing having an end formed with recesses, a shaft in said housing having an end portion adjacent the cover shaped to accommodate a force applying member, the other end of said shaft having a head portion, journal means extending transversely from diametrically opposed regions of the head portion, a roller carried by said journal means disposed on each side of said head portion engageable in the recesses in the sleeve for establishing a releasable drive connection between the shaft and sleeve, a plurality of stacked spring discs in said housing disposed between said sleeve and said cover for biasing the sleeve into engaging relation with the rollers, and means establishing a connection between said housing and sleeve whereby said sleeve is rotatable with the housing and longitudinally slidable relative thereto.

4. A predetermined torque release wrench of the character disclosed, in combination, a tubular housing having a closed end and an open end, means formed on the closed end adapted to accommodate a work engaging tool, a cover for the open end of the housing, said cover being arranged for adjustment relative to the housing, a sleeve in the housing having an end formed with recesses, a shaft in said housing having an end portion adjacent the cover shaped to accommodate a force applying member, said shaft having a head portion, journal means extending transversely from diametrically opposed regions of the head portion, a roller carried by said journal means disposed on each side of said head portion engageable in the recesses in the sleeve for establishing a friction drive connection between the shaft and sleeve, a plurality of stacked spring discs in said housing disposed between said sleeve and said cover for biasing the sleeve int-o engaging relation with the rollers, a thrust member between the end of the shaft and the a roller journally mounted on each projecting portion 01 closed end of the housing, and means establishing a connection between said housing and sleeve whereby said sleeve is rotatable with the housing and longitudinally slidable relative thereto.

5. A predetermined torque release wrench construction including, in combination, a housing having an open end, a sleeve slidable in said housing, a closure for the open end of the housing having threaded connection with the housing, a torque transmitting shaft extending through said sleeve and an opening in said closure, a portion of said shaft adjacent the closure being shaped to receive a manipulating handle for rotating said shaft, an end of said sleeve having recesses formed therein, means carried by the housing and engaging the sleeve for preventing relative rotation between said sleeve and housing, a pin carried by the shaft and extending transversely thereof and having portions projecting from the shaft, 4'1

the pin and engageabl with the recesses insaid sleeve, said housing having a closed end formed with a portion adapted to be connected with a work engaging means, resilient means biasing said sleeve into engagement with said rollers, the biasing pressure of the resilient means being controlled by adjusting said closure relative to the housing, a thrust element between the end of the shaft and the closed end of the housing, said shaft and housing being arranged for concomitant rotation by movement of the handle whereby force applied to the handle is transmitted through said sleeve and rollers to a limit at which the biasing pressure of the resilient means is exceeded and the rollers disengaged from the recesses in said sleeve.

References Cited in the file of this patent UNITED STATES PATENTS 

